The present invention relates to a dental hand tool and more particularly, to a dental prophy angle for cleaning and polishing teeth.
Prophy angle is a term of art given to a small, rotary powered hand tool used uniquely by the dental profession for cleaning and polishing teeth. As originally constructed, the prophy angle comprised an integrated combination of an air turbine motor for directly driving a single, elongated drive shaft. The entire construction was of either die cast aluminum or machined stainless steel.
The drive shaft length was confined within a tubular housing that served as the tool handle. The length of the tool handle and hence the length of the drive shaft, was and is dictated by user convenience and manipulation facility. This is generally considered to be about 4 to 6 inches. The turbine rotor vane elements were secured to one end of a stainless steel drive shaft and an angle drive transmission gear on the other shaft end. The drive shaft gear teeth meshed with the pinion gear teeth of a short shaft that was confined to rotation about an axis aligned substantially normally to the drive shaft axis. A projected end of the short shaft included an implement spindle to which a brush or polishing head, for example, was selectively attached.
Prudent medical practice requires that all dental tools used in intimate proximity of a single patient be sterilized before reuse on another patient. Normal dental office sterilization processes include the use of a superheated steam autoclave. Construction parameters for dental tool turbines, however, require that they be extremely small and light. These characteristics dictate small and extremely fragile turbine vanes and radar bearings. As a further consequence of miniaturization, the cost of such turbines is relatively great.
Due to the fragile construction, repeated autoclave exposure rapidly accelerates the decline and failure of dental tool motors. This fact and the relatively high cost of the turbines has inspired further innovations to the tool type. Such further innovations include a segmented drive line whereby the turbine motor is separable from the handle or gripping tube that carries the drive shaft. Further, the gripping tube is separable from the implement spindle head. In this configuation, it is unnecessary to autoclave the turbine motor. Only the gripping tube segment and the spindle head need to be sterized after use.
As a still further innovation, the spindle head has been fabricated with injection molded plastic components with such economy that a spindle head is discarded after a single use. Hence, only the gripping tube segment of the tool assembly remains for autoclave sterilization. Unfortuantely, disposeability of the spindle head has widely induced an unsafe disposition among some dental care practitioners that the gripping tube need not be sterilized.
An additional objection to a segmented driveline for dental tools is the tendency for such designs to produce a greater degree of vibration at high rotational speeds near 5,000 rpm due to the intermediate driveline mass that is located at the coupling between the spindle head and the motor coupling.
One object of the present invention, therefore, is the provision of a disposable prophy angle attachment.
Another object of the invention is a disposable prophy angle attachment having sufficient length to require only a single drive shaft coupling between a dental tool motor and the prophy angle implement.
A further object of the invention is an elongated prophy angle attachment having low medial shaft vibration.
Also an object of the invention is a unitary prophy angle attachment having a minimum of only four functional components, each of which are formed by extrusion molded plastic and are collectively assembled with such simplicity as to economically justify disposal after a single use.
An additional object of the invention is a prophy angle attachement that justifies and encourages sanitary practices.